1. Field of the Invention
The present invention relates to a fan assembly.
2. Description of the Related Art
Up until now, fan assemblies have been used in various equipment such as OA (Office Automation) equipment and electrical household appliances to cool parts or air that are heated due to the heat generated while driving the equipment. In particular, the amount of heat generated during the operation of CPU chips and other LSI's (Large Scale Integrations) has increased for personal computers and server equipment in accompaniment with dramatic increases in the processing speed. Fan assemblies that are more compact, have increased capacity, and have higher efficiency are therefore required.
A fan assembly such as shown, for example, in FIG. 12 to FIG. 15 is known in the art. FIG. 12 is a cross-sectional view along a line D-D shown in FIG. 13, which is a bottom view of the conventional fan assembly 100. FIG. 14 is a cross-sectional view depicting near a cable fixing member. FIG. 15 is a cross-sectional view depicting the cable fixing section along a line E-E shown in FIG. 14. An arrow denoted by F in FIG. 12 schematically depicts the flow of air.
As shown in FIGS. 12 to 14, the fan assembly 100, which is a centrifugal fan assembly, includes a fan 13 having a number of vanes 12 at a peripheral edge of a rotor 11, a motor 15, positioned coaxially to the inside of the rotor 11, that rotates the fan 13, and a casing 20, housing the fan 13 and the motor 15. The casing 20 has air inlets 16 and 17 in the direction of the axis of rotation of the fan 13 and having an air outlet 18 in a radial direction of the fan 13. Air taken in through the air inlets 16 and 17 is then ventilated from the air outlet 18 by rotation of the fan 13.
The rotor 11 is cylindrical and has a top portion 11a and a side portion 11b. A hole 20a in the casing 20 is for screwing the casing 20 to a printed wiring board 42.
The rotor 11 of the motor 15 functions as the fan 13. Namely, the rotor 11 includes a rotating shaft (motor) 14 installed vertically from a center part of the inner wall of the top portion 11a and a magnet (motor) 22 provided at an inner peripheral surface of the side portion 11b. The rotating shaft 14 is made of metal.
A stator of the motor 15 includes a bearing (motor) 23 that supports the rotating shaft 14 in a freely rotating manner, a support member (motor) 24 that supports this bearing 23, fixed to a motor mounting member 130, a control substrate 27 mounted with a control IC 26 that controls drive current etc., and a coil 25 fixed to the control substrate 27.
The motor mounting member 130 is for mounting the motor 15. The motor mounting member 130 is arranged so that a part of the bottom surface of the casing 20 near the air inlet 17 projects further outwards (downwards) than another outer surface portion 21 of the casing 20. The motor mounting member 130 is connected to a peripheral edge of the opening of the air inlet 17 by three to four ribs 131.
As shown in FIG. 12 to FIG. 15, a cable 40 from the control substrate 27 is ran along the outer surface (bottom) of the casing 20, is led to outside of the casing 20, and is connected to a connector 41 on the printed wiring board 42.
Fan assemblies where portions corresponding to the motor mounting member 130 do not project outwards (downwards) from the other outer surface portion of the casing are also known. Such a fan assembly has been disclosed in Japanese Laid-open Patent Publication No. H. 2004-52735.
A large fan assembly is necessary to cool devices and LSI's generating a large amount of heat. In particular, in the conventional fan assembly shown in FIGS. 12 to 14, the motor mounting member 130 projects further outwards (downwards) than the other outer surface portion 21 of the casing 20. It is therefore not possible to ensure sufficient air duct space between the motor mounting member 130 and the printed wiring board 42. Moreover, such an arrangement reduces the degree of freedom with regards to assembly layout and mounting and means that the assembly is large.